NICE AND EASY: Does an antenna need power?

Well, you’d think the answer would be nice and easy, but it isn’t.

An antenna does not need to be plugged into a wall socket, except when it does. That doesn’t help a lot, does it?

Let’s explain.

An antenna itself is just a metal stick. It doesn’t need power to function. What an antenna is doing is actually receiving a broadcast from the air. When a signal is broadcast, what really happens is a massive amount of electricity is pumped into the air. Air doesn’t transmit electricity very well. So, that electricity gets weaker and weaker as it gets further and further away.

When we say that your antenna “receives” a signal, we really mean something different. The physics are pretty complex so I’ll make it simple. (This also means my answer won’t be quite as accurate, so get ready for the haters.) When the antenna signal reaches the antenna, the antenna’s molecules begin vibrating in a way that corresponds to the antenna signal. A weak electrical signal then flows through the antenna and into the cable. If you’re using a coaxial cable, a very tiny amount of that signal is lost in converting from the 300 ohm impedance of the antenna to the 75 ohm impedance of the coaxial cable. But otherwise, there’s no external power needed.

Unless… you have an amplified antenna.

Amplified antennas do need power from a wall socket but it’s not the antenna that needs power, it’s the amplifier. The whole purpose of an amplifier is to read a weak signal, add power from an external source (like the wall) and create a stronger signal. So an amplified antenna is always going to need power. Most amplified antennas won’t work without a power source because the amplifier circuits are built right into the antenna so the signal just gets stopped if there’s no power to the amplifier.

If you have an amplified antenna, you also need to make sure the cable running to it has a solid copper center conductor. Most “home store” cables don’t… their cables have copper plating over a zinc center. That kind of cable won’t carry the electricity that the amplifier needs. That’s why you’ll want a high-quality cable like the ones we sell at Solid Signal.

If you use the wrong cable, you’re likely to think that your antenna just doesn’t work. The amplifier won’t be doing its job and you’ll be unhappy. Even worse, the amplifier might give you a little benefit but not as much as it should. This is due to the voltage loss over the cable. As the amplifier struggles to get the power it needs, you’ll get some improvement sometimes. And sometimes you’ll get no improvement. The amplifier won’t last as long and will break sooner, too.

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About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.